The National Asset Management Agency (Nama) will write off close to €30 billion of the €90 billion in property loans it buys from Irish banks when it completes the process of revaluing the debt over the next 12 months.

Government sources have indicated that the discount, or “write-down”, applied to the loans being transferred to taxpayers will be in the range of 30%, valuing the assets acquired at just above €60 billion.

The discount is higher than many analysts have predicted. That will be good news for taxpayers because it reduces the exposure they would face by owning billions of euros of over-valued property assets.

The lower the price paid by Nama, the better the possibility the agency has of recovering the state’s money in the long term.

The size of the discount may present difficulties for banks which are heavily exposed to development sites likely to suffer the most severe write-downs in value when Nama completes its calculations.

In extreme cases, banks faced with a massive write-off of their property assets could require a capital injection from the state to repair their balance sheets.

Brian Lenihan, the finance minister, has indicated that loans secured against potential development land are likely to be treated harshly. It is believed that these will be calculated at current market value in the majority of cases as these sites have few medium-term prospects of increasing in value given the oversupply of property already on the market.

Sources close to the government said Nama will pay an annual interest rate of just 1.5% on the bonds it will issue to the banks as payment for their property portfolios.

If the assets are valued at €60 billion, that means Nama will pay the banks €900m a year in interest. However, the agency expects to take in more in interest payments from the best performing parts of the property it is acquiring.

The Sunday Times has also learnt that the Green party has secured a commitment from Lenihan that a provision will be included in statutory regulations that will set aside Nama-controlled land for social purposes.

The agency will be able to stipulate that any landbank it sells on to construction companies for future development will have areas marked for community facilities such as school buildings as well as green spaces for parks and playing pitches.

Asked about government indications that the property loan write-down could be on a scale approaching ¤30 billion, one source said: “I think that would be the extremity of it but there will be a lot of number crunching over August.”

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